1. Field of the Invention
The present invention relates to a heat sink fan which cools an electronic component such as MPUs.
2. Description of the Related Art
MPUs (microprocessing unit) are incorporated in an electronic calculator and high performance electronic equipment. In recent years, as the MPU is increased in speed and reduced in size, heat generated from the MPU itself becomes serious problem. Therefore, a heat sink fan comprising a combination of a heat sink having a plurality of heat radiating fins and an axial flow fan for supplying air to the heat sink is incorporated in the electronic equipment such as the MPU which generates heat.
The heat sink is positively cooled by cooling air supplied by the axial flow fan.
The MPU is contained on a circuit substrate of the electronic equipment, and a power supply terminal which functions as a power supply of the heat sink fan is also provided on the circuit substrate of the electronic equipment. The heat sink fan is provided with a connection terminal and a lead wire to be connected to the power supply terminal. A base end of the lead wire is soldered to a drive circuit of the axial flow fan, and a tip end of the lead wire is connected to the power supply terminal.
Various electronic components are densely disposed in the vicinity of the MPU in which the heat sink is placed. To prevent a lead wire from coming into contact with such electronic components and from being cut, it is preferable that the length of the lead wire is set to the shortest length from a drive circuit of the axial flow fan to a power supply terminal.
However, the power supply terminal is not always disposed in the vicinity of the MPU, and the distance and the layout relation between the MPU and an external power supply are different depending upon the kinds of the electronic equipment on which the MPU is to be mounted in some cases. This problem can be solved by changing the length of the lead wire depending upon the corresponding kind, but if the same kinds of axial flow fans having different lead wire lengths as those of the electronic equipment are prepared, there is an adverse possibility that operators working at the producing worksite may confuse, and the productivity may be deteriorated. Further, if commonality of the lead wire lengths can not be achieved, costs of production facilities and costs of acquisition of parts are increased. Therefore, it is necessary that the lengths of the lead wires correspond to a kind in which a distance between the MPU and the external power supply is the longest.
In the case of electronic equipment having excessively long lead wire, the lead wire may be damaged or cut as described above. Further, at the time of packing operation, transportation and assembling operation, the lead wire may be caught on an impeller or housing made of resin, and such members made of resin may be damaged.
Thereupon, it is conceived that the heat sink is provided with a fan holder to which a fan is assembled, a surface of an outer periphery of the fan holder is provided with one or more grooves for partially restraining the lead wire, and the lead wire is accommodated in the groove. According to this structure, however, another member, i.e., the fan holder is required in addition to the axial flow fan and the heat sink, and it is troublesome to pass the lead wire through the groove, and this deteriorates the productivity.